The long term goal of this research is to learn more about hemostatic and fibrinolytic mechanisms and their abnormalities, which include the hemorrhagic and thrombotic diseases. An attempt to elucidate the phylogenetic development of the complex human hemostatic mechanism involves a study of coagulation parameters in many different vertebrates. Projects planned for this next year are: (1) A study of coagulation and other hematological parameters in Amphibia, especially the bullfrog. (2) Adaptation of an immunofluorescent technique to demonstrate fibrin split products in leukocytes. (3) Study of VIII activity, VIII antigen, and ristocetin cofactor in hemophiliac and von Willebrand disease families. (4) Study of placental antigens in abnormal pregnancies. (5) Study of special patients with bleeding problems.